The present disclosure relates to an indicator of oxygen generation in cosmetic formulations.
Oxygen is essential to sustaining life. Marine life utilize oxygen in dissolved form whereas land based species including humans utilize gaseous oxygen. The lack of oxygen or hypoxia is commonly experienced by people in their extremities (e.g. feet) as they get older due to poor blood circulation as well as by those with conditions such as diabetes. Studies have also shown below normal, low oxygen tension in the skins of older people. This often leads to poor skin health and an excessive presence of visible conditions such as wrinkles, dryness and lower skin elasticity. Over the years, cosmetic manufacturers have introduced skin formulations with a large variety of ingredients such as emollients, exfoliators, moisturizers etc., to retard these age related effects and improve and maintain skin health.
While some cosmetic formulators have focused on maintaining moisture, natural oils and providing nutrients to the skin, others have taken a different approach. This approach has looked at the role of oxygen from the medical point of view e.g. in treating of the compromised skin (wounds, inflammation and trauma) and more recently, intact skin. For example, Ladizinsky patented an oxygen generating wound dressing (U.S. Pat. No. 5,792,090), that is unfortunately somewhat difficult to manufacture. More recently, Gibbins et al. patented a method of making an oxygen generating foam dressing based on a polyacrylate polymer (U.S. Pat. No. 7,160,553). While the method of making an oxygen generating foam dressing is straightforward, the dressing itself suffers from a few drawbacks. For instance, the shelf life of the dressing is insufficient because oxygen from the dressing diffuses out of the foam cells over time. An alternative to the foam dressing in the form of an on-demand oxygen generating topical composition was proposed to overcome the limitation of the short shelf life (Ladizinsky US2009/0074880).
Unfortunately the catalytic decomposition of hydrogen peroxide to oxygen is quite rapid and the end user of such a composition has no way of observing if the mixing of the two parts has been thorough. An indicator system that could undergo some kind of visual change would be advantageous for broad acceptance of the product.
There is a need for an indicator system for ensuring thorough mixing of the two parts of the topical composition before or during its application to the skin. Indicator systems based on dyes and colorants have been used in variety of other applications, e.g. an indicator system to show proper cooling of a beverage as indicated by a color change upon reaching a certain temperature. An indicator system based on dye or pigment for an oxygen generating topical composition would require the use of a coloring ingredient whose by-product of discoloration may not suitable for the skin. Additionally, its color changing property could be unevenly affected by a variety of ingredients that are typically present in cosmetic formulations, rendering the product performance unpredictable.